In order to simultaneously transport as many vehicles as possible, current car-carrying vehicles conventionally incorporate several load-carrying decks of variable and adjustable height, on which cars or other motor-driven vehicles and, generally, road-hauled loads are successively loaded, transported and unloaded.
When the load-carrying vehicle is halted, it is sometimes necessary for the operator to assemble upon the load-carrying platforms and move along them, in order to perform certain technical or maintenance operations, or even just to perform simple safety checks—for example, to level or detach the transported vehicles, to gain access to a vehicle to be unloaded, or simple to lower the load-carrying platform after having loaded a vehicle to be transported.
While the operator can easily move around on the load-carrying platforms when they are unloaded, the situation is very different once they have been loaded with vehicles to be transported.
This is because, so as to optimize the transportation, the load-carrying area is generally filled to the greatest possible extent with vehicles to be transported, positioned such as to leave as little space as possible, especially laterally for the movement of an operator. The widest can attain or even sometimes slightly extend beyond the lateral edge of the platform on which they are loaded.
Therefore, the operator is required to walk very near the lateral edge of the load-carrying platform, which is impractical and rather unsafe for the upper platform of the car-carrying vehicle, even if fall-prevention systems are installed.
However, it is not possible to make larger load-carrying platforms that incorporate an additional area left free for passageway for the operator. This is because, when traveling, the car-carrying vehicle is supposed to comply with the various road or rail gauges applicable to it.